The primary objective ot this study is to evaluate the effect of combination therapy with HIVIG (administered beginning between 20-30 weeks of pregnancy and to the newborn within 12 hours of birth), and ZDV (administered intrapartum and to the newborn for 6 weeks), compared to IVIG and ZDV, administered similarly, on the incidence of HIV infection in infants born to HIV-infected women who are receiving ZDV for medical indications.